Improvement in chemical telegraphs



G.LITTLE.

GHEMIUAL TELEGRAPH.

No. 108,496. Patented Och-18, 1870..

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Letters Patent No. 108,496, dated October 18, 1870.

IMPROVEMENT lN CHEMICAL TELEGRAPHS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Be it; known that I, GEORGE Lrrrnnfot ltuthcrford Park, in the county of Bergen and State of New Jersey, have invented an Improvement in Circuits for Chemical Telegraphs; and the following is declared to be a correct description thereof.

Chemical telegraphs, in which the mark is made on a strip or surface of paper by a stilus, have usually only been worked at the end of a main line, because provision had not been made whereby drop copies,

or several copies could be made on one main line.

Recently derived circuits or shunts have been em ployed in the line-wire of the main circuit For effectas is necessary, where each copy is taken, and the re-' maiuder returns by tho earth-circuit.

In the drawing I have represented a diagram illustrativeof the improvement.

The wire (4 represents the main line from one station to another.

1) represents the roller, and c the stilus of any chemical telegraph, which,- bcing well known, requires no further description.

The roller and stilus, at each stat-ion where a. drop copy is to be taken, are in a branch or leakage-circuit between the main line a and the. ground.

The pulsations of electricity from the sending station will pass through a short circuit in preference to a long circuit, if the conducting power is uniform; hence, if several chemical telcgraphs were connected with the'main line, without a resistance or rheostat between the instrument and the main line, the pulsations would pass almost, if not exclusively, through the first instrument, to avoid which a resistance is to be introduced, as at e, between each instrument and the main line, and this resistance is to be proportioned by any of the well-known adj ustablc methods, so that only the amount of galvanic electricity necessary to make the mark is allowed to pass or leak from the main circuit to make the drop copy at the desired stations, the other portion of the current-I proceeding to the distant station, and, atthe last station, any surplus electricity may pass to the earth by the connection shown at g.

The resistance may be a coil, a column of mercury, or any other device that is adapted to the purpose, and I prefer to employ a resistance that is adjustable or variable, so as to proportion the resistance to the current.

By the use of several branch or leakage-circuits, connected to the earth, the main line is cleared ot'surplus electricity with much greater rapidity than in the arrangements heretofore employed; and hence, the

mark on the chemical paper will be more distinct, and, p

in cases where desired, a resistance and leakage-circuit to the earth may be employed to clear the wire, even when achemical recording instrument is not employed.

I claim as my invention- 1. A branch-circuit connected with the mainline and the earth, in which is placed the chemical telegraph and a resistance between that and the main line, substantially as and for the purposes set forth.

2. A branch-circuit and resistance, connected from the main line to the earth, for clearing the wire of surplus electricity, substantially as set forth.

Signed by me this 26th day of August, A. D. 1870.

GEORGE LITTLE.

Witnesses:

CHAS. H. SMITH, Gno. T.-P1NOKNEY. 

